Backport "Use sampler-based Random API (#206)" (#305)

This also backports the changes in PR #270, #278.

Project.toml

@@ -3,13 +3,16 @@ uuid = "53c48c17-4a7d-5ca2-90c5-79b7896eea93"
 version = "0.8.5"
 
 [deps]
+Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]
+StableRNGs = "1"
 julia = "1"
 
 [extras]
+StableRNGs = "860ef19b-820b-49d6-a774-d7a799459cd3"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test"]
+test = ["StableRNGs", "Test"]

src/FixedPointNumbers.jl

@@ -7,9 +7,10 @@ import Base: ==, <, <=, -, +, *, /, ~, isapprox,
              big, rationalize, float, trunc, round, floor, ceil, bswap, clamp,
              div, fld, rem, mod, mod1, fld1, min, max, minmax,
              signed, unsigned, copysign, flipsign, signbit,
-             rand, length
+             length
 
 import Statistics   # for _mean_promote
+import Random: Random, AbstractRNG, SamplerType, rand!
 
 using Base.Checked: checked_add, checked_sub, checked_div
 
@@ -326,8 +327,15 @@ scaledual(::Type{Tdual}, x::AbstractArray{T}) where {Tdual, T <: FixedPoint} =
     throw(ArgumentError("$X is $bitstring type representing $n values from $Xmin to $Xmax; cannot represent $x"))
 end
 
-rand(::Type{T}) where {T <: FixedPoint} = reinterpret(T, rand(rawtype(T)))
-rand(::Type{T}, sz::Dims) where {T <: FixedPoint} = reinterpret(T, rand(rawtype(T), sz))
+function Random.rand(r::AbstractRNG, ::SamplerType{X}) where X <: FixedPoint
+    X(rand(r, rawtype(X)), 0)
+end
+
+function rand!(r::AbstractRNG, A::Array{X}, ::SamplerType{X}) where {T, X <: FixedPoint{T}}
+    At = unsafe_wrap(Array, reinterpret(Ptr{T}, pointer(A)), size(A))
+    Random.rand!(r, At, SamplerType{T}())
+    A
+end
 
 if VERSION >= v"1.1" # work around https://github.com/JuliaLang/julia/issues/34121
     include("precompile.jl")

src/precompile.jl

@@ -1,3 +1,5 @@
+using Random
+
 function _precompile_()
     ccall(:jl_generating_output, Cint, ()) == 1 || return nothing
     normedtypes = (N0f8, N0f16)                      # precompiled Normed types

test/fixed.jl

@@ -1,4 +1,4 @@
-using FixedPointNumbers, Statistics, Test
+using FixedPointNumbers, Statistics, Random, StableRNGs, Test
 using FixedPointNumbers: bitwidth
 
 # issue #288
@@ -404,6 +404,8 @@ end
         @test ndims(a) == 2 && eltype(a) == F
         @test size(a) == (3,5)
     end
+    @test !(rand(Q0f15) == rand(Q0f15) == rand(Q0f15)) # If this fails, we should suspect a bug.
+    @test rand(StableRNG(1234), Q0f7) === 0.531Q0f7
 end
 
 @testset "floatmin" begin

test/normed.jl

@@ -1,4 +1,4 @@
-using FixedPointNumbers, Statistics, Test
+using FixedPointNumbers, Statistics, Random, StableRNGs, Test
 using FixedPointNumbers: bitwidth
 
 # issue #288
@@ -595,6 +595,8 @@ end
         @test ndims(a) == 2 && eltype(a) == T
         @test size(a) == (3,5)
     end
+    @test !(rand(N0f16) == rand(N0f16) == rand(N0f16)) # If this fails, we should suspect a bug.
+    @test rand(StableRNG(1234), N0f8) === 0.267N0f8
 end
 
 @testset "Overflow with Float16" begin